In single-plate solid-state imaging devices, different color filters are stacked on adjoining pixels formed on the same photodetecting surface. Therefore, color contamination may caused by oblique incident light. Solid-state imaging devices are configured in such a manner that signal charges corresponding to quantities of light beams incident on plural photodiodes (pixels), respectively, which are arranged in two-dimensional array form on a semiconductor substrate are stored in the respective photodiodes and signals corresponding to the amounts of the stored charges are read out as shot image signals.
In the case of solid-state imaging devices for taking a color image, a color filter layer is stacked over a semiconductor substrate on which photodiodes are formed and microlenses for condensing incident light onto the photodiodes are provided on the color filter layer so as to correspond to the respective photodiodes. Since there is a distance between the photodiodes and the microlenses, if incident light shines obliquely on the photodetecting surface, incident light that has passed through a red filter, for example, may shine on, instead of a red detection photodiode, a blue or green detection photodiode that is adjacent to the red detection photodiode, resulting in color contamination. If color contamination occurs at many positions, the hue of a subject image is varied and the image quality is degraded.
In particular, in imaging apparatus incorporating a photographic lens having a small F value, color contamination occurring at peripheral pixels on the photodetecting surface of a solid-state imaging device has serious influence because a subject optical image shines on those pixels at large incident angles. In recent years, solid-state imaging devices called a back illumination type have come to be incorporated in digital cameras. Whereas having high shooting sensitivity by virtue of a large aperture ratio, back-illumination-type solid-state imaging devices have a considerable distance between microlenses and a color filter layer which are formed on the back surface side of a semiconductor substrate and photodiodes which are formed on the front surface side of the semiconductor substrate, which is a structure that is prone to color contamination.
Among conventional techniques for correcting for color contamination is one disclosed in the following Patent document 1. In this conventional color contamination correction technique, in performing correction processing on a detection signal of a certain pixel of attention using signals detected by pixels around the pixel of attention, correction parameters are used that are obtained taking into consideration that pixels located on a certain direction have greater influences on the pixel of attention, that is, the four pixels around the pixel of attention do not influence the pixel of attention isotropically.